1. Field of the Invention
The present invention relates to an electrically-driven liquid crystal lens, and more particularly, to an electrically-driven liquid crystal lens wherein electrodes are defined with a vertical or horizontal rubbing direction, achieving improved lens-profile effects, and a stereoscopic display device using the same.
2. Discussion of the Related Art
At present, services for rapid dissemination of information, based on high-speed information communication networks, have developed from a simple “listening and speaking” service, such as current telephones, to a “watching and listening” multimedia type service based on digital terminals used for high-speed processing of characters, voice and images, and are expected to be ultimately developed into cyberspace 3-dimensional stereoscopic information communication services enabling virtual reality and stereoscopic viewing free from the restrains of time and space.
In general, stereoscopic images representing 3-dimensions are realized based on the principle of stereo-vision via the viewer's eyes. However, since the viewer's eyes are spaced apart from each other by about 65 mm, i.e. have a binocular parallax, the left and right eyes perceive slightly different images due to a positional difference therebetween. Such a difference between images due to the positional difference of the eyes is called binocular disparity. A 3-dimensional stereoscopic image display device is designed on the basis of binocular disparity, allowing the left eye to view only an image for the left eye and the right eye to view only an image for the right eye.
Specifically, the left and right eyes view different two-dimensional images, respectively. If the two different images are transmitted to the brain through the retina, the brain accurately fuses the images, giving the impression of a real 3-dimensional image. This ability is conventionally called stereography.
Technologies for displaying the above-described 3-dimensional stereoscopic images may be classified into a stereoscopic display type, volumetric measurement type, and hologram type. Of these types, the stereoscopic display type may be classified into two types, one using 3D glasses and the other not using glasses. In turn, the type not using glasses may be classified, based on the shape of a structure used for 3D realization, into a parallax barrier type and a lenticular type. A discussion of lenticular type stereoscopic displays follows.
Hereinafter, a conventional lenticular type stereoscopic liquid crystal display device will be described with reference to the drawings.
FIG. 1 is a perspective view illustrating a conventional lenticular type stereoscopic liquid crystal display device, and FIG. 2 is a sectional view illustrating the stereoscopic liquid crystal display device of FIG. 1.
As shown in FIG. 1, the conventional lenticular type stereoscopic liquid crystal display device includes a liquid crystal panel 10 consisting of upper and lower substrates 10a and 10b with liquid crystals 10c filled therebetween, a backlight unit 20 located at a back surface of the liquid crystal panel 10 and serving to direct light toward the liquid crystal panel 10, and a lenticular plate 30 located at a front surface of the liquid crystal panel 10 and serving to realize stereoscopic images.
As shown in FIG. 2, first and second polarizers 11 and 12 are attached to an upper surface of the upper substrate 10a and a lower surface of the lower substrate 10b, respectively.
The lenticular plate 30 is fabricated by forming a material layer, having a convex-lens-shaped upper surface, on a flat substrate.
When images, having passed through the liquid crystal panel 10, exit the lenticular plate 30, the viewer's eyes perceive different groups of images, thereby perceiving 3-dimensional stereoscopic images.
In the above-described conventional stereoscopic liquid crystal display device, the lenticular plate 30 and liquid crystal panel 10 are supported by structures (not shown) and thus, the first polarizer 11 on the liquid crystal panel 10 is spaced apart from the lenticular plate 30 by a predetermined distance.
With this configuration, however, the liquid crystal panel 10 or the lenticular plate 30 may droop or bend into a space between the first polarizer 11 on the liquid crystal panel 10 and the lenticular plate 30. This bending phenomenon results in abnormal optical pathways through the backlight unit 20, liquid crystal panel 10 and lenticular plate 30, thereby deteriorating image quality.
To reduce the space between the liquid crystal panel 10 and the lenticular plate 30, inserting an adhesive between the liquid crystal panel 10 and the lenticular plate 30 to attach the liquid crystal panel 10 and lenticular plate 30 to each other might be considered. However, the greater the area of the liquid crystal panel 10, the greater the required amount of the adhesive. Moreover, the adhesive problematically causes deterioration in transmissivity.
The above-described conventional stereoscopic display device has the following problems.
With relation to attachment of the above-described lenticular lens, there are problems, such as the use of an adhesive, deterioration in visual sensitivity due to the bending phenomenon causes, or a difficulty in the processing of a smooth lenticular lens.